Improvement of Edge Delamination Strength of Composite Laminates Using Adhesive Layers

Abstract

A thin but tough adhesive inner layer placed in laminates at the proper interface has been found to give improved delamination strength. Static tension tests of laminates with (±302/˙903/∓302)T and (±35/0/90)s layups of graphite/epoxy show that the added adhesive inner layer effectively suppresses delamination until final failure. The effects of adhesive layers on interlaminar stresses and strain-energy release rate have been studied analytically using a finite-element method. It was found that the introduction of adhesive layers reduced the interlaminar stresses. Although there was no significant change in total strain-energy release rate, there was a significant decrease in the G1 (tension mode) percentage of the total strain-energy release rate.